LeetCode 1436. 旅行终点站

示例 1：



输入：paths = [["London","New York"],["New York","Lima"],["Lima","Sao Paulo"]]

输出："Sao Paulo" 

解释：从 "London" 出发，最后抵达终点站 "Sao Paulo" 。本次旅行的路线是 "London" -> "New York" -> "Lima" -> "Sao Paulo" 。

示例 2：



输入：paths = [["B","C"],["D","B"],["C","A"]]

输出："A"

解释：所有可能的线路是：

"D" -> "B" -> "C" -> "A". 

"B" -> "C" -> "A". 

"C" -> "A". 

"A". 

显然，旅行终点站是 "A" 。

示例 3：



输入：paths = [["A","Z"]]

输出："Z"

class Solution:

    def destCity(self, paths: List[List[str]]) -> str:

        # 用字典形式存储地点

        resDict = dict()

        for iList in paths:

            #如果地点存在，就删除【因为本来就是对数存在】，不存在就添加，并记录是起点还是终点

            for index,val in enumerate(iList):

                if val in resDict:

                    del resDict[val]

                else:

                    resDict[val] = index

        for key,val in resDict.items():

            #val== 1为终点位置

            if val == 1:

                return key









if \_\_name\_\_ == '\_\_main\_\_':

    paths = [["London","New York"],["New York","Lima"],["Lima","Sao Paulo"]]

    ret = Solution().destCity(paths)

    print(ret)